Suggestions on doing a investment property loan involving 1031 money?

[Mary Chen]

My parents are planning on selling their investment home (SFR) to buy another home in Hawaii (i.e. 1031). They expect to not qualify on a loan (since income is likely too low) so my siblings and I want to cover it. We are looking multi-family and duplexes so the prices are definitely higher. What's the formula to determining how much money we are able to borrow? Also if we cover the loan, does that mean we are partial owners to the new property? Is % based on how much each party contributes? Any suggestions on types of loans with the least amount of headaches?